Functionalized semiconductor quantum dots have previously been demonstrated to bind to markers on cells. Through their spectrally-narrow optical emissions, they illuminate tumors and other harbingers of disease. They are enabling the highly specific detection of a range of diseases at the earliest stages. We propose to pursue a new and improved class of semiconductor quantum dots. We have shown already that, by seeding the growth of nanoparticles using a DNA template, we are able to produce quantum dots that are efficient, stable emitters in the infrared wavelengths (so-called biological window) in which living organisms are much more transparent than in the visible wavelengths, and in which living organisms'autofluorescence is orders of magnitude lower than in the visible. These materials retain their luminescence properties over time even in biological media such as plasma at 37o C. The collaborating team of Dr. Shana Kelley, a nucleic acids chemist, and Dr. Edward Sargent, an optoelectronics engineer, bring the expertise required to optimize the DNA-grown nanoparticles for applications in medical diagnosis. The strategy of directing the growth of luminescent nanoparticles using DNA provides a one-pot route towards the strong coupling of light-emitting tags with DNA-based aptamers for programmable specific-binding. The project is divided into the following Specific Aims: 1) Direct the growth, and thereby maximize the performance, of DNA-templated quantum dots using designer DNA sequences;2) Discover optimized DNA sequences for specific binding assays using in vitro selection. We will thereby develop new means of creating highly luminescent nanomaterials for medicine and biology. The team, with its complementary expertise in biomolecular chemistry and optical materials, is equipped with the infrastructure and resources to make a significant contribution to the realization of improved visible and infrared fluorophores for diagnosis.